Internal combustion engines



United States Patent Inventor: Austin C. Mercer, Jr.

Bradford, England Application No.: 697,826 Filed: Jan. 15,1968 Patented: Aug. 4, 1970 Assignee: Mercer Engineering Company (Bradford) Limited Bradford, York, England Priority: Jan. 20, 1967 Great Britain No. 3118/67 INTERNAL COMBUSTION ENGINES 4 Claims, Drawing Figs.

Primary E.ru/111'11er Mark M. Newman AtwrneyNorris and Bateman ABSTRACT: A rotary internal combustion engine comprising a cylinder assembly mounted for rotation about an axis and having an opposed pair of closed outer end cylinders at the inner ends of which is a common combustion chamber. Respective pistons reciprocate in the cylinders. A combustible 123/44 mixture is introduced into the cylinders at their outer ends for 133/74 compression during outward movement of the pistons, and Int. Cl. "1 02b 37/04, passage means i the ylinder walls is provided for transferring FO2b33/08 the compressed mixture to the combustion chamber. The Field ot'Search 123/44C, pistons act to valve the passage means, and both fuel intake 44D, 44E. 44. 74A and exhaust from the combustion chamber.

19 4.6 5,4 1% 5O L i\ Patented Aug. 4, 1970 Sheet Om Pm @v US. PATENT 3,522,796 INTERNAL COMBUSTION ENGINES The invention relates to rotary internal combustion engines and has for its object to provide an improvement therein. In particular, it is an object of the invention to provide an engine which has a minimum of moving parts (especially reciprocating parts), the pistons of which are easily sealed by conventional means, that is to say, by means of circular piston rings as opposed to the kind of sealing means employed to seal rotary pistons which rotate within trochoidal chambers.

According to the invention, there is provided a rotary internal combustion engine having at least a pair of cylinders, respective pistons which are slidable in said cylinders being connected to follower means for engaging an annular track through a slot or slots in the side wall of each cylinder. The outer ends of. said cylinders are preferably closed so that the combustible mixture can be fed to the outer end portion of each cylinder where it will be compressed during radially outward movement of the pistons and transferred to the inner ends of the cylinders through respective transfer passages. Ports in the cylinder walls are preferably covered and uncovered by the pistons during their reciprocation. Preferably, also the inner ends of the cylinders are interconnected, that is to say, in the case of a two cylinder engine, they are constituted by a single cylindrical bore diametrically disposed with respect to an axis about which a cylinder block containing said bore is rotatable. There may be two annular tracks spaced apart one within the other so that, during normal running of the engine, the follower means which are connected to the pistons will engage with and ride around the outer track but, when the engine is being started, said follower means will engage with and ride around the inner track. The two tracks may be spaced apart slightly more than the width of the follower means, for example when the follower means are in engagement with one cam track there will be a clearance between it and the other cam track which clearance may be in the order of approximately 0.010". Alternatively, there may be only a single track against which the rollers will be forced by centrifugal force and by pressure within the combustion space during the firing stroke.

In order that the invention may be fully understood and readily carried into effect, a preferred embodiment thereof will now be described, by way of example only, with reference to the accompanying drawings of which:

FIGURE 1 is a perspective partly cut-away view of an engine embodying the invention,

FIGURES 2, 3 and 4 are diagrammatic views illustrating successive sequences during the operation ofthe engine, and

FIGURE 5 is a somewhat diagrammatic axial section through the engine.

Referring now to the drawings, an engine embodying the invention has a cylinder block rotatably mounted in bearings 12 in a casing 14. A pair of opposed cylinders are constituted by a single cylindrical bore 16 which extends perpendicular to the axis about which the cylinder block is rotatable, and respective double-ended pistons 18 and are slidable in said cylinders. The pistons each have piston rings 19 in grooves in their end portions.

The pistons 18 and 20 are connected to follower means for engaging an annular track constituted by the surfaces of a pair of hard metal inserts 22 and 24 which flank the rotatable cylinder block. Said follower means are constituted by respective pairs of rollers 26, 28 and 30, 32 which are mounted on diametrically disposed gudgeonpins 34 and 36 which extend through the pistons midway between their ends and through respective slots, 38, 40 and 42, 44 in the side walls ofthe cylinders. As shown in FIGURES 2, 3 and 4, the shape ofthe track is defined by two intersecting circles with slight humps at the intersections. It will thus be seen that, as the cylinder block rotates, the pistons are caused to reciprocate within their cylinders as they follow the shape of the track. Conversely, as the pistons are forced outwardly by combustion of fuel mixture during a part of the revolution of the cylinder block, the

reaction of the track against the rollers causes the cylinder block to rotate. A stub shaft'l5 (shown in FIGURE 5, for purposes of illustration only, to be formed integrally with the cylinder block) extends through one end of the casing for power take-off. A further stub shaft 17 which extends through the other end of the casing is bored out to receive a sparking plug 88 which extends into the combustion chamber between the cylinders. A spring loaded rotary connection is provided between the sparking plug and a High Tension lead 90, and a distributor (not shown.) is provided to supply current to the sparking plug in timed relation to the rotation of the engine.

The outer ends of the cylinders are closed by means of respective end caps 46, 48 and spaces 50 and 52 which are thereby formed at the outer end portions of said cylinders communicate by way of respective transfer ports 54 and 56 with oppositely disposed transfer ports 58 (only one of which is shown in FIGURE 5) by means of transfer passages 60 and 62 shown diagrammatically in chain-dotted lines in FIGURE 5. The transfer ports 58 are disposed so that they are uncovered by the piston 20 when the latter approaches the outermost limit of its travel. An exhaust port 60 is disposed so that it is uncovered by the piston 18 when the latter approaches the outermost limit of its travel, and an exhaust passage 62 connects said port to a space 64 within an end cover 66 at one end of the easing into which cover an exhaust pipe 60 is connected. At the other end of the casing, an inlet pipe 70 (from a carburettor not shown) is connected into an end cover 72 and communicates with a space 74 which surrounds a plurality of ports 76 in the output shaft, which ports in turn communicate with one end of an axially disposed passage 78 in said shaft. The other end of said passage communicates, by way of respective inlet passages 80 and 82 (shown diagrammatically in chain-dotted lines in FIGURE 5 with inlet ports 84 and 86 which open into the two cylinders. Said inlet ports are disposed so that they are uncovered by the pistons when the latter approach the innermost limits of their travel so that the fuel mixture can flow into and fill the spaces 54 and 56.

When running, the engine operates on the 2-stroke cycle and there are thus two firing strokes per revolution of the cylinder block (since each piston makes two complete reciprocations per revolution). As the pistons are being forced inwardly by the engagement of their rollers with the annular track, a charge of fuel mixture is drawn into the spaces 50 and 52. Further rotation of the cylinder block then allows the pistons to move outwards as they are acted upon by pressure in the combustion space (that is to say by combustion of a previous charge) and the charge of fuel mixture in the spaces 50 and 52 is first compressed and then transferred to the combustion space from which it scavenges the spent gases from the previous charge. The cycle is then repeated.

Thus there is provided a rotary internal combustion engine, which has a minimum of moving parts and the pistons ofwhich are sealed by conventional means. The only reciprocating parts are the pistons, and it will be seen that since these move in unison in opposite directions the engine is inherently balanced.

Various modifications may be made without departing from the invention. For example, it is not necessary for the two cylinders to be interconnected; they could be quite separate one from the other (but in this case of course they would each require separate sparking plugs and separate inlet and exhaust ports). Furthermore, the engine could have more than two cylinders; it could have three cylinders for example and these may or may not communicate at the axis of the block with a common combustion space. There could be a further annular track spaced within the track constituted by the inserts 22 and 24 by a distance slightly greater than the diameter of the rollers. The rollers will then engage with and ride around this inner track when the engine is being started but will be clear of its surface during normal running by perhaps 0.010" or thereabouts.

I claim: 1. A balanced rotary internal combustion engine comprising a casing, a cylinder assembly mounted on said casing for rotation about an axis, and having internal walls defining opposed piston receiving cylinders, means for closing the outer ends of said cylinders, pistons mounted in said cylinders for reciprocation normal to said axis, there being a compression space in each said cylinder between said end closing means and the outer end of the associated piston and a common combustion chamber in said cylinder assembly at the inner ends of said pistons, cooperating cam and follower means on the pistons and easing responsive to rotation of said cylinder assembly for cyclically displacing said pistons inwardly toward said axis, fuel inlet passage means having ports in said cylinders adapted to be uncovered by said pistons when said pistons have moved a predetermined distance toward said axis for introducing fuel mixture into said compression spaces and covered by said pistons upon outward displacement of said pistons, means defining two transfer passages located wholly within the cylinder assembly each having at one end a port located at the outer end of a compression space and at the other end a port open to said combustion chamber, said ports at said other ends being covered by one of said pistons during movement of said pistons outwardly to compress the fuel mixture in said compression spaces and being uncovered to permit transfer of the compressed fuel mixture into the combustion chamber after predetermined outward movement of said pistons during the compression stroke, and exhaust passage means having a port open to said combustion chamber covered by one of said pistons during inward displacement and uncovered by said piston following combustion and predetermined outward displacement thereof whereby the transferred fuel mixture scavenges said combustion chamber of spent gases.

2. A rotary internal combustion engine having a casing, at least one cylinder in said casing rotating about an axis. the ends of said cylinder being closed, a pair of pistons slidable in opposite end portions of said cylinder, there being a compression space in each said cylinder end portion between said end closing means and the outer end of the associated piston and a common combustion chamber in said cylinder at the inner ends of said pistons, fuel inlet passage means having ports in said cylinder adapted to be uncovered by said pistons when said pistons have moved a predetermined distance toward said axis for introducing fuel mixture into said compression spaces and covered by said pistons upon outward displacement of said pistons, means defining two transfer passages located wholly within the walls of said cylinder, each passage having at one end a port located at the outer end of one of said compression spaces, and at the other end a port open to said combustion chamber, said ports at said other ends being covered by one of said pistons during movement of said pistons outwardly to compress the fuel mixture in said compression spaces and being uncovered to permit transfer of the compressed fuel mixture into the combustion chamber after predetermined outward movement of said pistons during the compression stroke, and exhaust means having a port open to said combustion chamber covered by one of said pistons during inward displacement thereof and uncovered by said pistons following combustion and predetermined outward displacement thereof whereby the transferred fuel mixture scavenges said combustion chamber of spent gases.

3. A rotary internal combustion engine according to claim 2, wherein said cylinder is formed in a rotatably mounted cylinder block.

4. A rotary internal combustion engine according to claim 3, operating on a 2-stroke cycle. 

